Camshaft - bolt removal sequence - calling anyone who's had a 4.2 head off

[nathanrobo]

As per the title, I struggling to comprehend the removal sequence for the bolts on the camshaft. Looking at the FSM on page EM24 it shows a sequence with 14 bolts shown, but a further 12 arrows that have no numbers shown - which is really strange.

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Any ideas? I'm sure it's something really obvious or implied??

 

[AndycruiserguyLomas]

I would guess thinking logically that you undo 1 then 2 and the two underneath then 3 and 4 and the one underneath and so on treating the even number bolts as a single unit.
I would undo them gradually even though there is a sequence (working outside to in) to avoid putting excessive bending force on the camshaft.

 

[nathanrobo]

Thanks for that... I think that I sussed it out after a while. So this is for anyone similarly confused:

If you look at the drawing below, you'll find three rows of bolts, with the row at the top and the 2nd row numbered. The rest just have arrows. The first two rows are for the camshaft bearing caps (where I guess there are bending stresses). The final - 3rd row are the bolts (12) hold in the rocker caps.

The FSM says:
A) remove the 13 bolts (I'm guessing that this is for the rocker caps 3rd row down?)
B) Uniformly remove the 14 bolts (top and 2d row??)
C) Remove 7 bearing caps, 12 rocker arms, 6 holder clamps, rocker shaft assy, and upper camshaft bearings.

So if I'm right the rocker caps are removed before the loosening sequence begins??

Can you confirm this??

 

[Towpack]

That's the procedure in the FSM for the 24v 1HD-FT engine fitted in the 80 series, the only difference being there are only 7 rocker cap bolts, not 13. These are removed prior to uniformly slackening and removing the 14 camshaft cap bolts.

 

[nathanrobo]

That's the procedure in the FSM for the 24v 1HD-FT engine fitted in the 80 series, the only difference being there are only 7 rocker cap bolts, not 13. These are removed prior to uniformly slackening and removing the 14 camshaft cap bolts.

Excellent... Thanks Sir!

 

[nathanrobo]

Bit of clarity...

for the 1HD FTE, there are 7 rocker cap bolts, it the injectors are still in there are also 6 clamps for the injectors. I guess this clears up the 7 vs. 13 bolts.

I took out the camshaft and rocker today. Left the head bolts for tomorrow. They are 12 point bolt heads and whilst I have 12 point sockets, they are only 3/8" drive. I reckon using a breaker bar to initially break the corrosion seal and slack off each bolt a couple of degrees (vs. loosening sequence), it would be safer to use an impact socket. Don't want any snapped sockets :-(

 

[nathanrobo]

Took the head off today and everything is in pretty good order. The pistons don't have much in the way of carbon, neither do the valves and the original honing looks like it was only just done (kinda what I expected with low mileage).

The head weighed a fair bit though, took two of us to lift it out.

I'll be off to the machine shop on monday to get the injector seats removed, then put it all back together.